USGS upgrading Oklahoma earthquake to 5.8 magnitude

Matt Skinner, public information officer at the Oklahoma Corporation Commission, answers a question at a news conference during a break in a workshop of Seismicity in Oklahoma, in Norman, Okla., Wednesday, Sept. 7, 2016. U.S. Geological Survey researchers say they're upgrading the strength of an Oklahoma earthquake that rocked the state over the weekend to a 5.8 magnitude, making it the most powerful earthquake ever recorded in the state. (AP Photo/Sue Ogrocki)
(The Associated Press)

Daniel McNamara, research geophysicist with the United States Geological Survey, answers a question at a news conference during a break in a workshop of Seismicity in Oklahoma, in Norman, Okla., Wednesday, Sept. 7, 2016. U.S. Geological Survey researchers say they're upgrading the strength of an Oklahoma earthquake that rocked the state over the weekend to a 5.8 magnitude, making it the most powerful earthquake ever recorded in the state. (AP Photo/Sue Ogrocki)
(The Associated Press)

Jeremy Boak, Director of the Oklahoma Geological Survey, gestures as he answers a question at a news conference during a break in a workshop of Seismicity in Oklahoma, in Norman, Okla., Wednesday, Sept. 7, 2016. U.S. Geological Survey researchers say they're upgrading the strength of an Oklahoma earthquake that rocked the state over the weekend to a 5.8 magnitude, making it the most powerful earthquake ever recorded in the state. (AP Photo/Sue Ogrocki)
(The Associated Press)

OKLAHOMA CITY – U.S. Geological Survey researchers say they're upgrading the strength of an Oklahoma earthquake that struck over the weekend to a 5.8 magnitude, making it the most powerful earthquake ever recorded in the state.

USGS research geophysicist Daniel McNamara said Wednesday the previous strongest recorded quake in Oklahoma — a 5.6-magnitude temblor in 2011 — also is being upgraded to a 5.7-magnitude quake.

Saturday's earthquake centered near the north-central town of Pawnee damaged more than a dozen buildings and left one man with a minor head injury after a fireplace collapsed.

McNamara says the volume of injected wastewater from oil and gas activity likely played a role.

He says Oklahoma's two earthquakes this year greater than magnitude 5.0 will increase the likelihood of larger quakes in the future.